Method of coking liquid hydrocarbons



Sept 27, l932- A. s. KNowLEs ,879,983l

METHOD OF COKING LIQUID HYDROGARBONS Filed Sept. 9. 1927 2 Sheets-Sheet l Sept 27, 1932- A. s. KNoWLEs L879,983

METHOD OF COKING LIQUID HYDROCARBONS Filed sept. 9, 1927 v2 sheets-sheet 2 55E/ye 'Patented sept. 27, 1932 UNITED STATES PATENT ol-ElcE ALEXANDER S. KNOWLES, OF (IHICAGI'O,` ILLINOIS, ASSIGNOB TO PETBOLEUI PROCESS COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION ILLINOIS METHOD F COKING LIQUID HYDBOCABBONS Application led September 9, 1927. Serial No. 218,453.

This invention relates to a new and im proved method for the treatment of liquid hydrocarbons for the removal of volatlle fractions and the coking of the residue into a form adapted for commercial use. This process'is adapted for the treatment of llquid hydrocarbons such as tars derived from the gas industry, coal distillation, wood and other distillation processes and also heavy mj oils or residues resulting from the distillation or cracking of petroleum or petroleum products. It is adapted for use with these and other materials liquid at normal temperatures or capable of being liquefied by moderate heat.

. In previous methods of treatment of such hydrocarbons, the volatiles` have been re moved to some extent with the formation of a more solid residue, which, however, is only suitable for special uses. These prior methods have been inefficient 'in that they have not successfully removed a high percentage of the volatile constituents and the'residue has been of a comparatively soft sticky nature 25 which renders diiicult its removal from the unit in which the treatment takes place,.and

which also renders its handling and trans-` f It isl an object of the present invention to provide a method of treatment in which the volatiles are driven oi and the solids recovered as a hard porous coke substantially free from ash and of considerable commercial value for many purposes.

It is a further object of this invention to provide a method of this character which is adapted for commercial utilization inv connection with apparatus of simple'design and construction. l

Other and further objects will appear as the description proceeds.

I have illustrated somewhat diagrammatically in the accompanying drawings a form of apparatus adapted for carrying out the` Figure 1 is a lon 'tudinal section of the'apparatus taken on e vertical plane; and

Figure 2 is a vertical transverse section. j

In the drawings I have shown aform of retort having a ioor 11 preferably formed of tile or similar material under refractor located a plurality of `lues'` 12. The

which is vburners 13 are provided by means of which combustion may be brought about in the flues 12. The iiues 12 lead to short downtakes 12 which ass into a waste heatliue 14. rIhe retortc amber 15 contains a basket 16 pon a shaft 17 journaled outside the ends o? the retort structure 18. One end of the shaft 17 is provided with a gar 19 by means of which the basket 16 may Y may be tubular and a pipe 20 is provided by means of which a gaseous fiuid may be introduced into the basket throu h the openings 20 in the hollow shaft. T e basket 16 is preferably formed of a heavy wire mesh o r other material adapted to permit passage of gases through the basket but to retain broken materials, such as coke, in the basket.

The longitudinal chamber 21, located above the axis of the basket 16, contains a ixed basket 22.- In the top of the chamber 21 is located la distributing pipe 23 provided with a plurality of spaced nozzles 21for the distribution of the liquid hydrocarbon. This is fed to the ipe 23 by means of the pipe 25 controlled y valve 26. The passa e 27 leads from the up er ortion of the .c amber 21 and serves Orth volatile products of the process.` The lower passages 30 are provided which may be used for the removal of gases or vapors liberated from the heavier material on the iioor. The

pipes 28 enter laterally into the lower portion s rotated. The-shaft .17

e withdrawal of the l of the retort chamber` 15 and serve to introl .duce steam orother gaseous medium as ma. be desired. The pipe 28 is controlled by valve 29. The end 31 of the chamber may be opened for removal of the basket and the coke on the floor through door 32.

In carrying out my may be removed process the basket 16 loo ' is partially filled with crushed material such retort chamber is thoroughly heated. The

as coke. It is preferably approximately three-fourths filled so as to maintain a large lmass of material and yet have esutlicient space so that the material is thoroughly turned over and agitated as the basket is rotated. Theupper stationary basket 22A is lilled with coke or other materialsuitable .for the purpose. The burners 13 are placed in operation and the .bottom floor 11 of the` temperature to be used varies depending upon the nature of the material being treated and also with the formation of the solid cokelike material upon the floor of the retort chamber. The heavy hydrocarbon to be treated preferably receives a preliminary heating suiiicient to bring it to approximately 100 degrees centigrade.

The valve 26 is opened and the liquid drops down through the openings 24 u n the coke or-other material in the fuel bas et 22. The volatiles are drawn off through passage 27 by means of a draft created in any desired manner. This draft causes passage of gases through the liquid-coated coke or other material in the basket 21 which serves to volatilize those fractions which are volatile Aat the comparatively low tem erature present at this point. The liquid drips from the basket 22 on to the basket 16 and on to and throu h the coke retained in this baswards the approaches the heated Hoor.

ket. It wi l be understood that the temperature gradually increases progressively tolower portion of the basket which The gases formed by volatilization in the basket pass through the coke in the basket and are carried oif upwardly. The unvolatilized residue gradually works its way down through the coke in the basket and dripsfrom the lower portion of the basket upon the highly heated Hoor 11. While the heat of this floor may be varied as above stated, depending upon the grade of material, I have found that temperatures varying from 500 degrees to 1000 degrees centrigrade generally are suitable. y

This liquid falling upon the floor has the remaining volatile content driven olf by thel high heat of the ioor and the residue forms a hard coke-like mass containing a very small percentage of ash and volatile matter. The volatile matter released on the floor from the heavier material there may be drawn olf through passage 30 on account of its greater specific gravity. A clearance of about six inches is suitable between the lower side of the basket and the Hoor 11, although this may be varied depending upon the heat it is desired to apply to the material in the basket and the depth of residue on the floor. It is found in usual practice that the liquid residue distributes itself over the entire Hoor and does not pile up immediately under the basket. When the solid residue has formed on the floor to a de th of three to ive inches, the process is pre rably temporarily stopped and the solid residue removed. It has been found that the coke in the basket becomes coatedwith the solid residue but does not appreciably grow in size and this coke need only be removed at long intervalsto maintain a uniform size and proper ercentage ofempty space in the basket. e end 31 ofthe c amber may be opened for removal of the basket.

. It will be apparent that the-temperature in the retort will gradually decrease during the accumulation of a layer of coke upon the floor 1l due to the insulating effect of this layer. This decrease in temperature may be compensated for by increase in combustion from the burners 13 so as to maintain the retort temperatures substantially-constant if desired. The rotation of the basket may be continuous or intermittent. v It is not normally desirable to rotate the basket rapidly as the hydrocarbons should adually pass down through the material. t will be apparent that thel rotationof the basket constantly presents new surfaces of the material to the liquid hydrocarbons falling into the basket and causes the liquid hydrocarbons to be gradually `carried down to the zone of higher tem erature caused by approach to the radiating oor 11. Thisv rotation is desirable in that it prevents ag lomeration of the coke in the basket and a so prevents channeling by the gases.

During-the process, steam or other gases may be introduced through pipe 20 and through the openings 20 into the mass in the rotating basket. This will serve to increase the current of ases released in the basket and carried o through the passage 27. Steam has the advantage of being readily removed from the gases upon their subsequent treatment. Steam may be introduced if desired throughl the pipes 28 laterally into the retort chamber.

It will be understood that the gaseous products of the process may be treated in any desired customary manner. They may be passed through a series of condensers operating at diferent temperatures so as to remove separately various condensible products. The steam may also be condensed out in this manner. The remaining gas may be used for any desired purpose. Steam has the disadvantage, however, of cooling the retort chamber. If desired, therefore, instead of steam any suitable gases may be used for introduction through pipes 20 or 28 to cause the gaseous circulation through the retort. A portion ofthe spent gases derived from the combustion below theI retort floor may be utilized if the final gaseous product of the process is not required to be of high heat value. If desired, a portion of the gases remaining after the condensation processes have taken place, may be returned to the retort through pipe 20 or 28 and recirculated.

VVhile I have specifically referred to coke as the material to be used in the baskets 16 and 22, it will be apparent that other materials may be used, such for example, as crushed-pumicestone, or metal, or any other material which may act as a catalyst in the breaking down of the heavier hydrocarbons. The size to which the material used is to be crushed may be varied with the viscosity of the material being treated. With a relatively liquid material small pieces of material may be used so as to retard the passage of the liquid through the retort and afford ample time for volatilization. Vith a relatively heavy liquid larger material may be used in the baskets, as this material will iow more slowly. The rapidity of rotation of the basket 16 also may be varied depending upon the viscosity of the liquid being treated and the timev required for the distillation of its volatilev constituents. Temperature control in the retort can also be effected by control lof the combustion in the heating flues below the retort iiool as well as by the rapidity of the circulation of gases through theretort and the temperature of the gases introduced into the retort for this circulation. It has been found in the operation of a plant of this character that there is not only the distillation of the volatiles from the liquid, but, where suitable materials are being operated upon, there is a definite crackin of the heavier constituents into lower bolling fractions. This cracking takes place not only in the basket but during the deposit of the'liqud dripping from the basket on to the floor.

It will be apparent, therefore, that my process oii'ers a very wide control of operating conditions so as to adapt it to treatment of a wide variety of hydrocarbons Whether normally liquid or capable of liquefaction at moderate temperatures. There is a complete recovery in merchantable form of the liquid being treated.A Although the oils recovered may normally be considered as the primary product of the process, the gas has fuel value and the coke-like product formed on the floor of the retort is of high commercial value. 'This latter fact is one of the features which particularly distinguish my process. In prior processes much of the solid residue has been of little commercial value and thus there is a lesser return from a considerable percentage of the carbon present in the liquid being treated. The solid product of my process is a hard'coke-like material which may be used as a metallurgical fuel and for many other purposes and is readily salable at high prices.

I claim:

1. The method of treating heavy liquid hydrocarbon material which comprises passing said material through a bed ofloose solid material that is substantially insoluble in said liquid hydrocarbon material and substantially infusible at a coking temperature, progressively increasing the temperature of the matel'ialbypassingitdownwardlythrough said bed, agitatingsaid material during the passage of the liquid hydrocarbon material, depositing the liquid residue in a layer upon a heated surface, and distilling and carbonizing the liquid on said surface.

2. The method of treating heavy liquid hydrocarbon material which comprises passing said material through a bed of lose solid material that is substantially insoluble in said liquid hydrocarbon material and substantially infusible at a coking temperature, progressively increasing the temperature of the material by passing it downwardly through said bed, agitating said material during the passage of the liquid hydrocarbon material, passing a gaseous current through said material to carry off the volatiles from the hydro- Y carbon material, depositing the liquid residue in a layer upon a heated surface, and coking the residue on such surface.

'3. The method of treating heavy liquid hydrocarbon material which comprises progressively heating the material by passing said material downwardly through a mass of loose coke which is progressively hotter toward the bottom, agitating the coke during the passage of the hydrocarbon material, permitting the liquid residue tol drip upon a surface heated to a coking temperature, and coking the residue on such surface.

4. The method of treating heavy liquid hydrocarbon material which comprises passing said material downwardly through a bed of loose coke, permitting the liquid hydrocarbon material to drip from said bed of coke to a second bed of coke, agitating the second bed of coke during the passage of the hydrocarbon material, permitting the liquid residue to drip from the second bed upon a surface heated to a coking temperature, and coking the residue thereon.

5. The method of treating heavy liquid hydrocarbon material which comprises progressively heating the material by distributing the liquid over a bed of loose solid material that is substantially insoluble in said liquid hydrocarbon material and substantially infusible at a coking temperature, heating said bed from below the same, permitting the unvolatilized liquid residue to drip from the bed upon a surface heated to a carbonizing temperature, driving ou the remaining vola tiles and forming a solid carbonaceous mass on the surface, and periodically removing said mass.

Signed at Chicago, Illinois, this 7th day of September, 1927.

ALEXANDER S. KNOWLES.

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